Scoring the Best Medical Device Cleaning Method: What You Need to Know

When choosing a new manufacturing cleaning process for medical devices, consider more than the cost of the equipment or the price of the cleaning fluid. It is the total “cost-per-part-cleaned that is important.” The cleaning method and fluids must effectively remove production contaminant like oil, grease, adhesives, fingerprints, flux, and adhesives. They must also be fast, safe, sustainable, compliant, and affordable.

With so many cleaning methods and fluids all claiming to work the best, it’s challenging to find a solution that works for specific requirements. Making a decision based on cost alone can be a costly mistake in the long run.

Choosing the least expensive machine or the cheapest cleaning fluid available isn’t always best. To make the best decision, have all the information before making the best, most informed choice. It is helpful to use a scorecard, or checklist of criteria, to support decision- making.  A cleaning scorecard captures all the details of the parts cleaning, highlights key factors to know to figure “total cost per part cleaned,” and determine the most viable cleaning answer.

Check Regulations Before the Start
Environmental regulations must be a priority to inform a cleaning choice. Regional and local laws are continually evolving—this makes selecting a cleaning fluid challenging, and the risk of making an incorrect choice higher. Decision-makers should understand local environmental regulations and invest in cleaning methods and fluids that comply. The chosen cleaning fluid should be sustainable well into the future. 

For example, nPB is a very effective and reliable medical device parts cleaner. This brominated solvent has been used for production cleaning inside vapor degreasers for decades. However, recent air quality scrutiny has caused nPB to be banned in several countries and it’s on the watchlist for phaseout in a number of others. A better option is to choose a more modern cleaning fluid based on HFO (hydrofluoroolefin) technology. These newer fluids have low GWP (Global Warming Potential) and zero ODP (Ozone Depleting Potential), which provide a lighter environmental footprint.

Be Cautious with Water
For those considering aqueous (water-based) cleaning, it’s not necessarily the most environmentally-forward choice. Water is becoming increasingly scarce in some parts of the world. Aqueous cleaning typically requires gallons of this precious, non-renewable resource.

Aqueous systems typically have high power requirements due to the need for several washing and rinsing stations, high temperature inputs, and reliance on mechanical spraying and washing mechanisms. Large amounts of electricity, gas, propane, or other power sources are often needed to heat the wash water, dry off the parts, then process used water for recycling.  All that washing, drying, and recycling increases your carbon footprint. Most equipment manufacturers can offer a guideline on energy costs.

In contrast, vapor degreasers use low boiling temperature fluids to clean and dry parts. They clean and dry parts in one cycle, cutting down on power use. The cleaning fluid is reused for thousands of hours as it continuously recycles inside the vapor degreaser before it must be distilled and replaced. For those looking for a more environmentally-sound solution, consider vapor degreasing as a viable option.

Consider One-Time Capital Costs
Up-front capital costs include the actual cost of the cleaning machine, freight, site preparation, and set-up costs. Include any building renovations, ventilation enhancements, electrical upgrades, and water-treatment subsystems required to support the new system. These one-time expenses can be as costly as the cleaning machine itself: include your facilities manager, environmental health and safety officer, fire safety team, and production department in the conversation to ensure capture of all the cleaning system’s requirements and associated costs.

Determine the Cleaning Throughput
Cleaning throughput can dramatically affect operating expenses. Knowing the cleaning throughput hourly rate is crucial to calculating the “total cost-per-part-cleaned” because operational and labor expenses are usually tabulated as hourly costs.

Evaluate the cleaning system’s average productivity to determine the number of parts cleaned per hour. For example, a machine that cleans 20 parts simultaneously in a 40-minute cleaning cycle has a throughput of one part every two minutes, or an average throughput of 30 parts per hour. Cleaning machine vendors should be able to provide benchmark numbers.

Another way to determine cleaning throughput is to estimate the total surface area of all the parts. This is useful with a large variety of parts with many different shapes. Remember to figure in other cycle time factors, including time needed for loading and unloading the cleaning machine.

Once you know the cleaning throughput, consider the machine. For example, if looking at vapor degreasers, determine their pros and cons. Large vapor degreasers are effective for fast, efficient high-volume automated cleaning. Smaller benchtop cleaning machines are slower, but considerably less expensive to buy and operate.

Calculate the Operating Costs
Once the throughput has been defined, it’s relatively easy to compute operating costs. Direct operating costs include the drag-out losses, electricity consumption, and required consumables such as saponifers or filters. Equipment manufacturers can provide basic guidelines for typical installations.

Drag-out is the loss of solvent due to being trapped in, on, and around the medical device parts as they move through the cleaning system. Look for optional equipment that helps eliminate drag-out losses. Extra refrigeration, superheat, and hoists on vapor degreasers help reduce drag-out losses and save money. Aqueous systems have similar money-saving options such as air-knives and extra drying chambers, which cut solvent losses but add to the electric bill.

Watch Out for Hidden Labor Costs
Remember to account for hidden costs like labor and maintenance. Labor should be calculated separately from other operating costs. In most instances, automatic equipment saves time on labor and maintenance. Many companies feel their automated cleaning processes are under control—they know how long it takes operators to load the machine, clean the parts, and unload them. But a closer review of their “automated” processes sometimes reveals technicians performing non-automated functions like auxiliary inspections, hand-spraying, re-cleaning, and drying of products outside the machine.

Remember to include the value of the engineer’s time, making sure the wash water or cleaning fluid remains within specs and waste treatment systems are operating correctly. Also include the cost of operator training, maintenance techs’ time, and any chemical safety training. If turnover is a problem, add additional funds for quarterly supplemental training.

Understand the Maintenance Costs
Aqueous cleaning machines include many moving parts and processes, from water treatment and recycling, to the alkaline additives used to boost cleaning power, to the blowers and air knives to dry the parts. All parts must be monitored and maintained. Vapor degreasing systems require filter changes and the cleaning fluid eventually needs boiling down for removal.

Modern cleaning fluids don’t require the extensive testing or monitoring of older solvents like nPB. The new fluids won’t ‘turn acid’ inside the vapor degreaser except under the most extreme conditions, like exposure to a strong base, acid, or extreme heat. They also don’t require the stabilizers, scavengers, or weekly acid acceptance testing required of older solvents.

Take a Test Drive
Once you determine the highest-scoring cleaning method, take a test-drive of the equipment from the manufacturer. Request a report on the cleaning process, cleaning fluids, temperatures, times, and results to ensure the system performs to required cleaning needs. Send samples to equipment makers to prove their systems’ ability to clean the components to your specifications. Eliminate systems that can’t do the job.

Prepare a batch of typical contaminated or dirty parts. Have each manufacturer run them through their cleaning systems. The manufacturer should be able to produce a brief written report describing the process, solvents, temperatures, times, and results. Ensure the systems perform to your standards. Do this testing first; this is the easiest part of the selection process.

Determine the Final Score
Finally, examine and calculate the chosen cleaning method to ensure it scores highly on every element and works effectively for specific requirements. The most important factor to keep in mind when completing a scorecard is the outcome; it doesn’t matter how much lower the cost of a cleaning process is if it doesn’t work. 

For those looking for help to choose the best medical device parts cleaning method, work with a precision cleaning expert specializing in both aqueous and vapor degreaser cleaning. They can help assess a particular cleaning project and recommend the fluid and process that offers the best cleaning performance. 

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Elizabeth Norwood is a senior chemist at MicroCare LLC, which offers precision cleaning solutions. She has been in the industry more than 25 years and holds a BS in chemistry from the University of St. Joseph. Norwood researches, develops, and tests cleaning-related products. She currently has one patent issued and two pending for her work. For more information, visit www.microcare.com.